Currently, a variety of forms of manufacturing tooling such as stamping dies, trim steels, flange steels and die inserts are formed from homogeneous, high cost, alloy tool steels, either from wrought or cast materials. The materials used are often determined by the properties of the working or cutting edges or die surfaces while the larger volume of the tooling merely supports these working surfaces and does not require the same physical properties as these working parts. When the working surfaces have worn to the point that the tooling needs to be replaced, the entire homogeneous structure is discarded. Similarly, stamping and injection molding and die casting dies often require modest changes during the design process as a result of last-minute engineering functional or aesthetic changes in the product. Presently this often requires the creation of an entirely new tool.
During the past few years methods and apparatus have been developed for creating net shape functional parts with close tolerances and acceptable residual stress levels involving the deposition of multiple thin layers of feedstock, one upon the other, using an energy beam to fuse each layer onto a substrate. A typical system is disclosed in U.S. Pat. No. 6,122,564. This patent discloses a laser-aided, computer-controlled direct metal deposition system (DMD™) wherein successive layers of material are applied to a substrate so as to fabricate an object or provide a cladding layer. This system is equipped with feedback monitoring to control the dimensions and overall geometry of the fabricated section in accordance with a computer-aided design description. The deposition tool path is generated by a computer-aided manufacturing system. Such feedback controlled systems may totally eliminate intermediate machinery and reduce final machinery considerably.
Such DMD systems are capable of depositing sections on metallic substrates of a differing material than used in the deposition, on the condition that suitable choices of material are made and suitable surface treatment is performed to achieve a good metallurgical bond between the deposited material and the underlying substrate.